The present invention relates to a manually-actuated fluid dispenser pump and to a fluid dispenser device including such a pump.
In known manner, a pump generally includes a pump body in which a piston is mounted to slide between a rest position and a dispensing position, said piston being moved by the user into its dispensing position in order to dispense the fluid contained in said pump, e.g. in a pump chamber. In conventional manner, the pump is provided with means for defining the rest position of the piston, and with means for defining the dispensing position of said piston. Such means are generally in the form of abutments that define the end positions for the piston. It is known that the abutment defining the dispensing position can be implemented by means of a shoulder in the pump body, so that, when the piston comes into abutment against said shoulder, it is no longer possible to move the piston any further relative to the pump body, thereby defining the actuating end position or dispensing position of the piston.
Unfortunately, such a configuration suffers from a drawback. Each time the pump is actuated, the sealing lip of the piston, and in particular the active portion of the sealing lip, i.e. the portion that forms the leaktight contact between the lip and the pump body, comes into abutment against the radial shoulder, so that the active portion is subjected to axial forces or stresses. After the pump has been actuated several times, that can cause the sealing lip of the piston, and in particular its active sealing portion, to be damaged or deformed, which can give rise to a deterioration in the performance of the pump. Similarly, while the pump is being assembled, it is frequent for the piston to be moved into its dispensing position by the assembly machine. That can occur relatively roughly, and in any event much harder than when the pump is used by the user. In which case, the bottom sealing lip comes into abutment quite roughly against the radial shoulder of the body of the pump while the pump is being assembled. That can cause the sealing lip of the piston to be degraded or damaged on assembly of the pump.
An object of the present invention is to provide a fluid dispenser pump that does not suffer from the above-mentioned drawbacks.
An object of the present invention is thus to provide a fluid dispenser pump that protects the piston, thereby avoiding any deterioration in the performance of the pump, and thereby increasing the life span of said pump.
An object of the present invention is also to provide such a fluid dispenser pump that is simple and inexpensive to manufacture and to assemble.
The present invention thus provides a manually-actuated fluid dispenser pump including a pump body and a piston mounted to slide in leaktight manner in said pump body between a rest position and a dispensing position, said piston being provided with at least a bottom sealing lip in leaktight contact with said pump body, said pump body being provided with an inwardly-extending radial shoulder co-operating with said bottom lip of the piston to form an abutment for said piston, and to define its dispensing position, said pump being characterized in that said pump body is provided with an axial annular setback at said radial shoulder so that the active sealing portion of the bottom lip makes no contact with said radial shoulder when the piston is in its dispensing position, so that no axial force is exerted on said active portion.
Advantageously, the bottom axial edge of the bottom lip of the piston is slanting, so that, when the piston is in the dispensing position, the non-active portion of the bottom edge is in abutting contact with said radial shoulder of the pump body, while the active sealing portion extends inside said annular setback.
The present invention also provides a fluid dispenser device including a pump as defined above.